The present invention relates to an alignment and connection mechanism for a mask-mounted regulator of a self-contained breathing apparatus.
A self-contained breathing apparatus (SCBA) is a type of supplied-air respirator which permits a person to breathe in hazardous environments such as fires and confined spaces where breathing would be difficult or impossible without mechanical aid. Examples of known SCBAs are the Custom 4500(copyright) MMR and Ultralire(copyright) MMR Air Masks from Mine Safety Appliances Company (xe2x80x9cMSAxe2x80x9d) which are shown and described in MSA Data Sheet No. 01-02-11-MC (2000), the disclosure of which is incorporated herein by reference. Typically, an SCBA includes a facepiece with a lens, a harness and carrier assembly, an air cylinder full of high pressure compressed air for breathing and at least one and preferably two air-pressure regulators. The first regulator is typically mounted on the harness and carrier assembly near the air cylinder and functions to reduce the relatively high pressure of the compressed air from the air cylinder to slightly above atmospheric pressure. The second regulator is often mounted on the facepiece and functions to adjust the flow of air to meet the respiratory needs of the user.
One such second-stage regulator is described in U.S. Pat. No. 5,016,627, the disclosure of which is incorporated herein by reference. Typically, second-stage regulators of this type are removeably mounted to the facepiece by inserting an outlet portion of the regulator into an inlet opening in the facepiece and locking the regulator in place. An example of one such second-stage regulator is the Mask-Mounted Regulator Assembly (P/N 812857) currently manufactured by MSA, which can be used with the Ultra Elite(copyright) pressure demand facepiece. As shown in the Parts List(s) and the Operation and Instructions Manual for MSA""s MMR Air Masks, the disclosures of which are incorporated herein by reference, the Ultra Elite facepiece from MSA includes a lens and a component housing cover having an inlet opening in the form of a circular hole. The outer edge of the inlet hole includes two opposed outwardly extending flanges. The corresponding mask-mounted regulator assembly includes an outlet portion in the form of a circular projection which will fit inside the inlet hole. Disposed near the base of the outlet portion are a pair of slots which correspond to the two flanges on the facepiece. A projection lies within each slot and is spring-biased in the direction of the outlet portion. One of the projections is attached to a sliding release mechanism on the outside portion of the regulator. In order to connect the regulator to the facepiece, one first aligns the slots on the regulator with the flanges on the inlet hole of the facepiece. Then the circular projection of the regulator is pushed into the inlet portion of the facepiece which causes the projections to be pushed inwardly by the flanges. Finally, the regulator is rotated a quarter-turn to lock the regulator in place. In order to disconnect the regulator, the release mechanism is pulled downwardly in a direction away from the facepiece so that the regulator can be rotated a quarter-turn and the flanges on the facepiece can align with the slots on the regulator. The regulator can then be pulled away from the facepiece enabling the user to breathe ambient air through the inlet opening in the facepiece rather than compressed air from the cylinder.
One drawback to this design is that an initial visible connection point is not provided between the facepiece and the regulator when the facepiece is being worn by a user. This often results in the user having some difficulty being able to quickly connect the second-stage regulator, particularly when wearing gloves. Misalignment between the regulator and facepiece often results in several trial and error attempts to make the connection between the facepiece and the second-stage regulator. It would be desirable therefore, to provide an improved connection mechanism between the facepiece and the second-stage regulator which includes a visible initial connection point on the facepiece to enable the user to more quickly connect the regulator to the facepiece.
Generally, the present invention relates to an alignment and connection mechanism which enables a regulator to be easily and quickly connected to the facepiece of a supplied-air respirator such as an SCBA. The alignment and connection mechanism of the present invention comprises an alignment member, preferably mounted on the regulator, and a guide member, preferably mounted on the facepiece. Alternatively, the guide member could be mounted on the regulator and the alignment member could be mounted on the facepiece. In either case, the member mounted on the facepiece is at least partially visible to the user through the lens when the facepiece is being worn.
In a preferred embodiment, the alignment member comprises a pair of arm members attached to and projecting from the regulator and the guide member comprises a pair of channels formed in each side of a ridge-like projection which is attached to the component housing cover of the facepiece. The user initially attaches the pair of arm members of the regulator to the channels in the guide member, preferably at a connection point on the guide member which is visible to the user through the facepiece lens. The regulator is then slid down the channels of the guide member so that the outlet portion of the regulator is properly aligned with and swings into the inlet opening of the facepiece. The regulator is then connected to the facepiece with at least one and preferably two spring loaded hook members by pushing the regulator into the inlet opening of the facepiece. The regulator is releasable from the facepiece by pushing in on at least one and preferably two release buttons located on the regulator.
The present invention is particularly advantageous in that a visible initial connection point is provided on the facepiece which the user can easily see while wearing the facepiece. This ensures a more accurate first alignment of the regulator with the facepiece resulting in a more rapid connection. Other details, objects and advantages of the present invention will become readily apparent from the following description of the present preferred embodiment thereof.